Server Access Problem

I recently changed my NT4.0 network to a Windows 2003 Network.
We have 6 remote offices. Five are conencted by frame relay, and one by VPN.
Once we upgraded to Windows 2003 Server from NT4.0, the office connected via VPN was no longer able to talk to the DNS/WINS server (all servers are at the main office). They can ping any server on the network except the DNS/WINS server.
When I try to use the DNS/WINS server to ping a computer on the remote network conencted via VPN it says: “Negotiating IP Security”.
I can’t figure it out because there are no log messages in the VPN router or the server.

HEEEEEEEEEEEEEEEEEEEEEEEELP!!!!!!!!!!
In the office